Effects of selective cyclooxygenase isoform inhibition on systemic prostacyclin synthesis and on platelet function at rest and after exercise in healthy volunteers

• Published in: Platelets (Edinburgh) Vol. 18; no. 5; pp. 379 - 385
• Main Authors: Weber, Artur-Aron, Heim, Hans-Karl, Schumacher, Marc, Schrör, Karsten, Hohlfeld, Thomas
• Format: Journal Article
• Language: English
• Published: England Informa UK Ltd 01.01.2007; Taylor & Francis
• Subjects: Adenosine Diphosphate - administration & dosage; Adult; Aspirin - administration & dosage; Aspirin - adverse effects; Atherosclerosis - complications; Atherosclerosis - enzymology; Cyclooxygenase 1 - metabolism; Cyclooxygenase 2 - metabolism; Cyclooxygenase 2 Inhibitors - administration & dosage; Cyclooxygenase 2 Inhibitors - adverse effects; Cycloxygenase; Double-Blind Method; Endothelium - enzymology; Epoprostenol - blood; Exercise; Humans; Isoenzymes - antagonists & inhibitors; Isoenzymes - metabolism; Lactones - administration & dosage; Lactones - adverse effects; Male; Platelet Activation - drug effects; platelets; prostacyclin; Rest; Risk Factors; Sulfones - administration & dosage; Sulfones - adverse effects; Thrombosis - enzymology; Thrombosis - etiology; thromboxane A; Thromboxane B2 - blood
• ISSN: 0953-7104; 1369-1635
• DOI: 10.1080/09537100601115919

To test the hypothesis that selective inhibition of cyclooxygenase (COX)-2 would result in exercise-induced platelet activation by causing a shift in the endogenous thromboxane (TX)/prostacyclin balance, a double blind, randomized study comparing aspirin (300 mg/d) with rofecoxib (25 mg/d) (cross-over design, 14 days washout between treatments) in n = 10 trained healthy volunteers was carried out. Physical exercise resulted only in a minor platelet activation, as reflected by the expression of basal or ADP-stimulated platelet activation markers or basal plasma concentrations of TXB2. Aspirin significantly reduced TXB2 in plasma while rofecoxib significantly increased TXB2 in urine. Although no increase in systemic prostacyclin concentration was observed, there was a significant exercise-related increase in both platelet cAMP and cGMP without any drug-related effects. It is concluded that, in trained healthy volunteers, selective inhibition of COX-1 (aspirin) or COX-2 (rofecoxib) does not affect systemic prostacyclin synthesis after physical exercise. However, our data do not exclude the possibility that in subjects at risk for atherothrombotic complications (e.g. patients with advanced atherosclerotic disease) COX-2 inhibitors may result in platelet activation by inhibiting endothelial prostacyclin formation.